For the past 2 months, my blog is exceeding the allocated bandwidth(30,000 MB) and I am unable to find out why! I have prevented hotlinking images using the IIRF filter this month.

I thought I could get some advice from the experts here on what should I look for more to find out what is causing me exceed my allocated bandwidth. Is there anything specific I need to look on? I have checked the logs/bandwidth reports, but unable to get anything out of it :(

What control panel have you got? If its Cpanel based you should be able to see exactly where your bandwidth is going. You need to compare the previous month to when the increased bandwidth came.. Given the bandwidth it may take time, but all of the info is there!

Any scripts other than WordPress hosted on your account? Could be a poorly constructed script accessing a file non-local (javascript file etc on another site). As others have mentioned could be a hotlinked image or other file (not hosting 'backed-up' MP3's a? ) or it could be a spider that doesn't conform to robots.txt instructions (have had this once a few years ago, spider was pulling down between 10 and 50 gigs a month crawling the site multiple times per day). Could be numerous things! Check your stats, see if you can get a raw log file and analyze that, it may give you a clearer picture if your bandwidth stats seem off. May also pay to check your email stats (most CP's have a way of looking into this) to see whether a script has been compromised and is being used to send SPAM or used for other malicious intent (although you'd quickly get your hosting cut off for this one). Also, if you've got a bit of time, keep on eye on your "latest visitors" log (as it is called in Cpanel), any files/images/pages getting an un-usual spikes in traffic?